The present disclosure relates generally to ventilation systems and, more particularly, to methods and systems for mixing airflows in environmental control systems.
In some known aircraft environmental control systems (ECSs), bleed from the aircraft's engines is injected as trim air into a conditioned air flow duct to adjust (i.e., raise) the temperature of the air supplied to the cabin or other compartment within the aircraft. The temperature of the trim air mixed with the conditioned air is used to regulate an amount of trim air that is injected into the conditioned air. In at least some known aircraft, the trim air is injected into the conditioned air flow at a T-joint or Y-joints of varying angles, and the airflow turbulence in the duct mixes the airflows. However, such turbulent mixing does not uniformly mix the airflows before a temperature measurement of the combined airflows is taken. Further, such mixing may limit the position of the trim air injection to only long, straight portions of the ducting. Additionally, it may be difficult to correctly position the duct temperature sensor in the duct to obtain an accurate temperature measurement. For example, if the duct temperature sensor is positioned too far from where the trim air is injected, the mixed airflow may experience heat loss through the duct by the time it reaches the duct temperature sensor leading to low temperature measurements at the duct temperature sensor. When the measured mixed airflow temperature is too low, additional trim air may be injected to warm up the air. However, using more trim air than needed results in the overuse of bleed air and reduces the fuel burn efficiency of the aircraft.